ES2877242B2 - TELESCOPIC TOWER CONSTRUCTION PROCEDURE - Google Patents

Description

DESCRIPTION

TELESCOPIC TOWER CONSTRUCTION PROCEDURE

FIELD OF THE INVENTION

The present invention refers to the civil engineering sector and, particularly, to tower construction techniques for supporting wind turbines. More specifically, the invention refers to a process for the construction of telescopic deployment wind turbine towers, by means of sequential formwork in height.

BACKGROUND OF THE INVENTION

The towers for wind turbines have traditionally been built in steel, with a frustoconical/cylindrical shape, made up of tubes with steel sheets, which form sections, which are joined together by means of flanges welded to the ends of each section. and with holes provided so that they can be joined together by means of screwed bolts.

Also, especially in the case of taller towers, concrete towers of various designs have been made. These towers can be made entirely of concrete or, on other occasions, they are hybrid towers, made of concrete up to a certain height and, from that height, they are made of steel tube. Regarding the structure of the concrete towers, there are many variants, with two main manufacturing possibilities:

- Concrete towers made from sections that are precast in molds and then moved into position where the tower is erected. Of these, in turn, there are different typologies: there are towers made from prefabricated rings, and towers made from prefabricated voussoirs that are later joined to form tubular sections, and it is these sections that are finally assembled, one on top of the other. , to form the tower.

- Although they are less abundant, there are also concrete towers manufactured in situ, through the use of sliding formwork or climbing formwork. These towers are built without any prefabrication process, placing formwork and concreting the tower in its final position section by section.

The use of cast-in-place concrete towers is not very widespread, because these towers present three major problems:

- The geometry of the tower is of variable diameter (around 6-9 m in diameter at the base, with 3-4 m at the top), which requires formwork to be replaced at each level of height (referred to as "climb") by a different formwork, or to forms whose geometry can be adjusted in each climb. This implies a high cost of the formwork and a lower efficiency, because the geometric adjustments of the formwork make them expensive and time consuming. and cost.

- The process itself is slow, taking place at maximum rates of approximately six meters of climbing every one or two days, which means 30-40 days of work to make a 120 m tower, which is a very insufficient rate to the construction deadlines that are usually handled in the sector.

- It requires cranes of considerable size for the climbs from a certain height, in addition to assuming a high inefficiency, given that the personnel and the necessary materials and tools must be raised to the height level at which they are going to work.

The result of these drawbacks is that the speed of construction is not sufficient, and multiplying the number of formwork and crane equipment significantly increases costs. This is why almost no in-situ concrete towers are built, even though in-situ concrete has the advantage of eliminating the requirement to use a factory to make the precast parts, as well as the transportation of said parts. These limitations generate, in the present technical field, the need to develop new construction techniques for telescopic towers, mainly applicable to in-situ concreting procedures, which improve the efficiency of known techniques. The present invention is intended to solve said need, by means of a new method for the construction of telescopic towers, which benefits from the execution of a sequential formwork in height of the plurality of sections that make up said towers.

BRIEF DESCRIPTION OF THE INVENTION

In light of the problems of the state of the art exposed in the previous section, an object of the present invention refers, mainly, to a procedure according to any of the claims of this document, which is based on a novel formwork system, specially designed for the execution of said procedure.

Thanks to the procedure of the invention, it is possible to build a concrete tower using the techniques of on-site construction, but in a more efficient and faster way, which also allows the total height of the towers to be increased without penalizing the process and means necessary. for the assembly of the wind turbine that has to operate at the top of the tower.

The proposed geometry of the tower is of the telescopic type, with sections of preferably constant section, circular or polygonal (for example, hexagonal), similar to the structure of a spyglass. In a preferred embodiment, the tubes that make up the tower have a constant section, but each tube has a different diameter, decreasing as it is placed at a greater height. The joints used to fix the definitive position of said tubes, as well as the joints between them, are inverted, so that a lower flange at the base of each tube protrudes outwards (it has a larger external diameter than the section itself) while that an upper flange on the tube head protrudes inward (has a smaller inside diameter). Thanks to this system of horizontal joints, it is achieved, firstly, that telescoping of the tubes is possible and, secondly, it is possible for the tower to have a growing diameter from top to bottom, which improves its structural efficiency.

The characteristic elements of the tower object of the invention reside, mainly, in its construction process, which is carried out using on-site manufacturing techniques, with a climbing or sliding formwork system. In addition, the process has the added peculiarity that said system allows the tower to comprise several tubes at the same time, where each tube is formed as a superposition of sections of formwork in height, preferably using a formwork with several internal faces and several faces exteriors, instead of the conventional formwork made up of a single exterior face and a single interior face.

This technique is used for at least two sections of the tower, and not necessarily for its entire length: there may be an upper part of each section that is prefabricated, or made of another material, or that is concreted one at a time. of two or more sections simultaneously.

Once the different sections of the tower have been manufactured with this technology, the prefabricated sections are raised to their final height, by using hydraulic jacks, or by any other technique.

The telescopic tower built according to the invention eliminates the problems inherent to the construction of in-situ concrete towers for wind turbines, incorporating the following advantages:

- The substantially constant section of each tube allows simple formwork, which does not need to be adjusted between one climb and the next. This means, therefore, the realization of formwork much faster and cheaper.

- Working on two or more sections in each climb or concreting height allows a much faster progress of the construction, since in each climb, in reality, the equivalent of two or more climbs is made according to traditional techniques, depending on the number of telescopic sections that are built with this technique.

- As the tower is telescopic and built folded, the working height on the climbs is limited to the length of a single section. However, with this it is possible to simultaneously build the sections that, once hoisted, will go higher. In this way, a significant cost is saved in construction cranes, as well as process time (working at heights between 5 and 50 m, instead of between 5 and 140 m).

- The assembly of the wind turbine can preferably be carried out before the telescoping of the tower, which reduces the height for its assembly and, consequently, reduces the cost and increases the availability of cranes with sufficient capacity for said assembly of the wind turbine.

The tower manufactured in this way preferably needs a specifically designed system, which has three types of formwork:

- An external formwork, which forms the outer face of the outermost section of the tower tube. This formwork is similar to that which would be used for any conventional tower with a constant section, but not telescopic.

- An interior formwork, which forms the interior face of the innermost section of the tower tube. It is also a conventional formwork, similar to what would be used to build any tower or shaft with this technology.

- One or more intermediate formwork, in the form of concentric double panel pieces, arranged between two concentric and contiguous telescopic tubes of the tower. Preferably, one of these intermediate forms is used if the tower has only two tubes made with this technology, two if it has three sections, and so on. Each of these formworks is, in fact, the sum of an internal formwork for the outermost section of the two sections between which it is placed and an external formwork for the innermost section of the two sections between which it is placed. They can be two independent forms or, due to the short distance between them, a single element with two formwork elements.

The tower manufacturing procedure, therefore, is based on each formwork/concreting/climbing process being carried out successively with all the formwork, so that the next climb begins when the previous climb has been finished. of all sections. Said succession can be carried out continuously, with processes analogous to those of sliding formwork, or by discontinuous advance stages, with processes analogous to those of climbing formwork.

Normally, in this type of telescopic tower, the shape of the flanges or finials at the upper and/or lower ends of each telescopic tube of the tower prevent the section from being completed with the same formwork. Thus, to make that part of the tower, prefabricated pieces can be used or a specific formwork can be used for these upper and lower areas of the sections.

The tower manufactured with this procedure may, in turn, be a hybrid tower, so that it has some sections made with this technology and some additional section, preferably in its upper part, made of another material or with another technology, preferably sections of conventional steel.

DESCRIPTION OF THE DRAWINGS

The above and other characteristics and advantages will be fully understood from the detailed description of the invention, as well as from the preferred embodiments referring to the attached figures, which are described in the following paragraphs.

Figures 1-2 show a telescopic tower with three concentric sections, a base tube and two drop-down tubes, in the states before and after the hoisting of said drop-down tubes, respectively.

Figure 3 shows a detailed view of the formwork of the invention, at a first height of the sections of the concentric tubes of a telescopic tower.

Figure 4 shows a detailed view of the formwork of the invention, at a second height of the sections of the concentric tubes of a telescopic tower.

Figures 5a-5d show successive phases of construction of different sections of the concentric tubes of a telescopic tower.

Figures 6a-6d show successive construction phases of the upper flanges of a telescopic tower with three concentric tubes.

Numerical references used in the drawings:

DETAILED DESCRIPTION OF THE INVENTION

A detailed description of the invention is set forth below, referring to different preferred embodiments thereof, based on Figures 1-6 of this document. Said description is provided for illustrative purposes, but not limiting, of the claimed invention.

As described in the previous sections, the invention preferably refers to a process for building telescopic-type wind towers (1), formed by a plurality of concentric tubes (2, 2', 2''), preferably including a base tube (2) and one or more tubes (2', 2'') that can be deployed in height, by mounting and lifting them.

An example of said towers (1) is shown in Figures 1-2 of this document, where a telescopic tower (1) is represented with a base tube (2) and two drop-down tubes (2', 2''), in the states before and after hoisting of said deployable tubes (2', 2''), respectively.

Mainly, the invention results from application to towers (1) in which the tubes (2, 2', 2'') are of the telescopic type and adopt a concentric configuration (as shown in Figures 1-2). However, it can also be applied to towers (1) in which only part of them is made up of telescopic concentric tubes (2, 2', 2''), while another part comprises any other type of section or tower section known in the art.

The process of the invention preferably comprises the following steps:

a) Build at least two concentric tubes (2, 2') of the tower (1) so that, provisionally, said concentric tubes (2, 2') are located essentially at the same height and one is housed inside another ( Figure 1). In a preferred embodiment of the invention, said concentric tubes (2, 2') are of the cylindrical type, which is advantageous as it maintains its geometry constant throughout its height. However, they can also adopt a frustoconical shape or any other geometry, within the scope of the invention. Similarly, in another preferred embodiment, the concentric tubes (2, 2') have walls of constant thickness for most or all of their height or, alternatively, they can be of variable thickness, with the same considerations as above. Likewise, in another embodiment, the section of the tubes (2, 2') is circular, but it could also be polygonal or of any other type, without thereby departing from the scope of the invention.

b) Raise at least one concentric tube (2') to deploy the tower (1) telescopically.

c) Connect different concentric tubes (2, 2') of the tower (1) to each other.

Likewise, and essentially in the invention, at least two of said concentric tubes (2, 2') of the tower (1) are made of concrete and are built, at least in part, with the axis of the tube ( 2, 2') in a vertical position and successively concreting different sections (3, 3') of said concentric tubes (2) at different heights. Said successive concreting allows different levels of the tubes (2, 2') to be completed, through the construction of a succession of sections (3, 3') in the shape of a ring, which are superimposed until said tubes (2, 2') are completed. ) with its definitive extension in height.

Advantageously in the present invention, step a) of the procedure comprises, in turn, the following sub-steps:

a1) Arrange formwork means (4) in a first concreting height. Said formwork means (4) can be, in different embodiments of the invention, of the climbing or sliding type, of the self-climbing type (that is, they can raise themselves), or they can be raised by other means, such as a crane. Likewise, the formwork means (4) can be made of metal, wood or any other material known in the art.

a2) Concreting, through said formwork means (4), first sections (3) of at least two different concentric tubes (2, 2'), said sections (3) being located at a first concreting height . Preferably, before concreting, the steel reinforcements or bars should be placed, which will be embedded in the concrete, as is known in the art. Said reinforcement can be assembled at the corresponding concreting height, but it can also be advantageous to pre-assemble it in the form of cages at ground level, in order to then lift said pre-assembled reinforcement cages, with a crane, to their corresponding height. This has the advantage that it allows more work to be done at ground level and not at height, and also allows the execution times of each section (3) to be shortened, since the pre-assembly of rebar cages can be brought forward, while, if assembles the rebar at the corresponding concreting height, said assembly cannot begin until the previous section has been completed.

Although, in a preferred embodiment of the invention, the concreting in sections (3, 3') of the tower (1) is carried out successively, said succession should be interpreted, in general, as any sequence of dispositions of the means of formwork (4) in height, including the situation in which the concreting is carried out, in whole or in part, without interruption, as is known in the art of sliding formwork (4). Therefore, concreting and lifting operations of the formwork means (4) can be performed simultaneously, without thereby departing from the scope of the invention.

Likewise, although the concreting of at least two concentric tubes (2, 2') is already advantageous in the present invention, in a preferred embodiment thereof said concreting will be carried out at each height of all the tubes (2, 2'). , 2'') concentric, which is a considerable advantage for the execution times of the tower (1) which, by means of the method of the invention, are substantially reduced compared to other alternatives of the state of the art. The procedure additionally avoids the need to hoist complete sections (3, 3') by means of high-capacity cranes, which also reduces the costs corresponding to the construction of the tower (1).

a3) Raise said formwork means (4) to a second concreting height. In order to facilitate said elevation, as well as the performance of other tasks, the formwork means (4) can incorporate another series of support elements, as is well known in the art and, in particular, elements to facilitate access and personnel working conditions, such as stairs, elevators, work platforms, etc. Likewise, in a preferred embodiment of the invention, in the lifting stage of the formwork means (4), they rest on the first sections (3) of the previously concreted tower.

In different embodiments, the formwork means (4) can be lifted by means of a crane or by means of lifting means incorporated in the formwork itself (such as those used in self-climbing formwork, known in the art). The formwork (4) can be raised, from a concreting height, directly to the next concreting height, but it can also pass through another intermediate position between both concreting heights, without thereby departing from the scope of the invention. For example, the formwork (4) can be lowered to ground level to clean it, adjust its geometry or any other action, before raising it to the next concreting height.

a4) Concreting, using the formwork means (4), second sections (3') of at least two different concentric tubes (2, 2'), said second sections (3') being located at a second height of concreting higher than the first concreting height of sub-stage a2).

Figures 3-4 show detailed views of the formwork (4) of the invention, at two different heights of the sections (3, 3') of its concentric tubes (2, 2').

In a preferred embodiment of the invention, the method further comprises the substep of:

a5) successively repeating sub-stages a3) and a4), going through multiple concreting heights and thus increasing, by arranging multiple sections (3, 3'), the height of at least two concentric tubes (2) of the tower (1) until said concentric tubes (2) reach the desired height. Preferably, for this embodiment, the formwork means (4) are reusable, so that they are removed after completing step a5), and can be reused in another location, for example to build another tower (1).

In another preferred embodiment of the invention, the formwork means (4) comprise double concentric panel pieces (5) (Figures 3-6) that allow formwork, in the same position, the outer face of a concentric tube (2) of the tower (1) and the inner face of another concentric tube (2') of the tower (1). More preferably, said concentric double panel pieces (5) are retractable and/or extensible, in such a way that they can be separated from the section (3) already concreted, thus facilitating their lifting prior to the concreting of the next section (3).

In another preferred embodiment of the method of the invention, at least part of the concentric tubes (2, 2', 2'') of the tower (1) comprise an upper flange (6) at the head of a concentric tube (2) and/or a lower flange (7) at the base of a concentric tube (2) (Figures 3-6), where said procedure further comprises the sub-step of:

a6) concreting, totally or in part, at least one upper (6) and/or lower (7) flange, in a position separated from the concentric tube (2) to which it belongs, thus generating a prefabricated flange piece. However, part of the concentric tubes (2, 2', 2'') and, in particular, for example the upper (6) or lower (7) flanges, can be built using different procedures, without thereby leaving the scope of the invention. Said different procedures may include, for example, prefabricating all or part of said flanges (6, 7), or, for example, employing specific formwork means (4) for concreting said flanges (6, 7). The prefabricated parts used in this way can comprise the entire flange (6, 7) or a part of it. In a preferred embodiment of the invention, the flange (6, 7) is made up in part of said prefabricated part and another part of the flange (6, 7) is cast in situ in contact with said prefabricated part.

In another preferred embodiment of the invention, the construction procedure further comprises, before sub-step a2), the sub-step of:

a7) arranging at least one prefabricated flange part of a lower flange (7) of a concentric tube (2) in the position in which said concentric tube (2) is to be built where, in substep a2), said concentric tube (2) is concreted, at least in part, on said flange prefabricated piece. In other words, the prefabricated flange piece can, for example, comprise the lower part of the lower flange (7), in such a way that it can act as a precast slab and/or lost formwork, to support the fresh concrete during concreting. another part of said lower flange (7).

In another preferred embodiment of the invention, the method further comprises, after sub-step a4), the sub-step of:

a8) arranging at least one prefabricated flange part of an upper flange (6) of a concentric tube (2) on a previously concreted section (3) of said concentric tube (2).

Figures 5a-5d show an example of successive phases of construction of different sections (3, 3') of three concentric tubes (2, 2', 2'') of a telescopic tower (1), according to a preferred embodiment of the invention.

In another preferred embodiment of the invention, for concreting at least part of the upper flanges (6) or lower flanges (7), a recoverable embedded formwork (8) is used, which is located between two upper flanges (6) and/or between two lower flanges (7) of contiguous concentric tubes (2, 2') during concreting. Preferably, the recoverable embedded formwork (8) comprises a panel with wedge geometry, to facilitate its removal. Said wedge shape facilitates the removal of said embedded formwork (8), by providing a certain draft angle to remove the panel from the space comprised between two previously concreted flanges (6, 7) (Figure 6).

The recoverable embedded formwork (8) that is located between the flanges (6, 7) of two contiguous concentric tubes (2, 2') can be recovered after concreting the flanges (6, 7). It can also be recovered, at least in part, during step b) thanks to the elevation of one of said concentric tubes (2') with respect to another (2). In this second case, when the tube (2') rises, it drags the wedge piece, so that, when it has risen enough, it can be removed.

In another preferred embodiment of the invention, the method further comprises the substep of:

a9) Placing a wind turbine (9) on said wind tower (1), using a wind turbine assembly crane where, during substep a7), said wind turbine assembly crane is used to hoist at least one prefabricated flange part of at least one upper flange (6) of a concentric tube (2) (Figure 6). This possibility is advantageous since the prefabricated parts of the upper flange (6) can be quite heavy and are located at a high height. Therefore, positioning them may involve high-cost cranes. By taking advantage of the crane that is going to be used in any case to assemble the wind turbine (9), synergies are generated in the operations and, with it, a reduction in execution times with the consequent cost savings.

Figures 6a-6d show successive construction phases of the upper flanges (6) of three concentric tubes (2, 2', 2'') of a telescopic tower (1), by using a recoverable embedded formwork (8), according to a preferred embodiment of the invention.

Claims (10)

1.

- Procedure for the construction of a telescopic type wind tower (1), comprising the following stages: a) build at least two concentric tubes (2, 2') of the tower (1) so that, provisionally, said concentric tubes (2, 2') are located, essentially, at the same height and one is housed inside other; b) raising one or more concentric tubes (2') to deploy the tower (1) telescopically; c) connecting different concentric tubes (2, 2') of the tower (1) with each other; where, at least, two of said concentric tubes (2, 2') of the tower (1) are essentially made of concrete and are built, at least in part, with the axis of said tubes (2, 2') in vertical position and concreting, successively, a plurality of sections (3) thereof; and said procedure being characterized in that step a) comprises, in turn, the following sub-steps: a1) arranging formwork means (4) at a first concreting height; a2) concreting, using said formwork means (4) simultaneously in the same operation, first sections (3) of at least two different concentric tubes (2, 2'), said sections (3) being located at said first concreting height; a3) raising said formwork means (4) to a second concreting height; a4) concreting, using said formwork means (4) simultaneously in the same operation, second sections (3') of at least two different concentric tubes (2, 2'), said second sections (3') being located at said second concreting height. two.

- Method according to the preceding claim, further comprising the sub-step: a5) successively repeating sub-stages a3) and a4), going through multiple concreting heights and increasing, by overlapping sections (3, 3'), the height of at least two concentric tubes (2, 2') of the tower (1), until said concentric tubes (2, 2') reach a desired height. 3.

- Procedure according to any of the preceding claims, wherein said formwork means (4) comprise double concentric panel parts (5) that allow formwork, in the same position, an outer face of a concentric tube (2, 2 ') of the tower (1) and an inner face of another concentric tube (2, 2') of the tower (1). Four.

- Method according to any of the preceding claims, wherein at least part of the concentric tubes (2, 2') of the tower (1) comprise an upper flange (6) at the head of the concentric tube (2, 2') and/or or a lower flange (7) at the base of the concentric tube (2, 2'); where said procedure further comprises the sub-step of: a6) concreting at least part of at least one upper (6) and/or lower (7) flange, in a position separated from the concentric tube (2, 2') to which it belongs, thus generating a prefabricated flange part. 5.

- Procedure according to the preceding claim, comprising, before sub-step a2), the sub-step: a7) arrange at least one prefabricated piece of flange of a lower flange (7) of a concentric tube (2, 2'), in the position in which said concentric tube (2, 2') is going to be built where, in the step a2), said concentric tube (2, 2') is concreted, at least in part, on said prefabricated flange piece. 6.

- Method according to claim 4, further comprising, after sub-step a4), the sub-step of: a8) Arrange at least one prefabricated flange part of an upper flange (6) of a concentric tube (2, 2') on a previously concreted section (3) of said concentric tube (2). 7.

- Procedure according to any of claims 4-6 where, for the concreting of at least part of the upper flanges (6) or of the lower flanges (7), a recoverable embedded formwork (8) is used, which is located between two upper flanges (6) to be concreted or between two lower flanges (7) to be concreted of adjoining concentric tubes (2, 2'). 8.

- Method according to the preceding claim, where the recoverable embedded formwork (8) comprises a panel with wedge geometry to facilitate its removal. 9.

- Method according to any of claims 7-8, where, during stage b), the recoverable embedded formwork (8) is recovered, at least in part. 10.

- Method according to any of claims 5-6, further comprising the substep of: a9) placing a wind turbine (9) on said wind tower (1) using a wind turbine mounting crane (10); where, during substeps a7) and/or a8), said wind turbine assembly crane (10) is used to lift at least one prefabricated part with a lower (7) and/or upper (6) flange of a concentric tube (2 , two').